msm: mdss: allow not having frame buffer memory

If pan_display is not used, the frame buffer memory is not reserved
and allocated. Adding checks to make sure no memory operations on
framebuffer.

Change-Id: Ia837d4ea0cad4e40e52ee5817c8d58e7db852a97
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>

3 files changed, 18 insertions, 3 deletions

diff --git a/drivers/video/fbdev/msm/mdss_fb.c b/drivers/video/fbdev/msm/mdss_fb.c
index 1ad818239391..08937c4cf259 100644
--- a/drivers/video/fbdev/msm/mdss_fb.c
+++ b/drivers/video/fbdev/msm/mdss_fb.c
@@ -657,6 +657,11 @@ static int mdss_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
 	struct msm_fb_data_type *mfd = (struct msm_fb_data_type *)info->par;
 
+	if (!start) {
+		pr_warn("No framebuffer memory is allocated.\n");
+		return -ENOMEM;
+	}
+
 	mdss_fb_pan_idle(mfd);
 	if (off >= len) {
 		/* memory mapped io */
diff --git a/drivers/video/fbdev/msm/mdss_mdp_overlay.c b/drivers/video/fbdev/msm/mdss_mdp_overlay.c
index ac1c4ce565d4..56fd163f17aa 100644
--- a/drivers/video/fbdev/msm/mdss_mdp_overlay.c
+++ b/drivers/video/fbdev/msm/mdss_mdp_overlay.c
@@ -1111,7 +1111,8 @@ static void mdss_mdp_overlay_pan_display(struct msm_fb_data_type *mfd)
 
 	fbi = mfd->fbi;
 
-	if (fbi->fix.smem_len == 0 || mdp5_data->borderfill_enable) {
+	if (!fbi->fix.smem_start || fbi->fix.smem_len == 0 ||
+	     mdp5_data->borderfill_enable) {
 		mfd->mdp.kickoff_fnc(mfd);
 		return;
 	}
@@ -1142,9 +1143,13 @@ static void mdss_mdp_overlay_pan_display(struct msm_fb_data_type *mfd)
 		goto pan_display_error;
 	}
 
-	if (is_mdss_iommu_attached())
+	if (is_mdss_iommu_attached()) {
+		if (!mfd->iova) {
+			pr_err("mfd iova is zero\n");
+			goto pan_display_error;
+		}
 		data.p[0].addr = mfd->iova;
-	else
+	} else
 		data.p[0].addr = fbi->fix.smem_start;
 
 	data.p[0].addr += offset;
diff --git a/drivers/video/fbdev/msm/mdss_mdp_util.c b/drivers/video/fbdev/msm/mdss_mdp_util.c
index 8bb30612339c..57051a3ef7f5 100644
--- a/drivers/video/fbdev/msm/mdss_mdp_util.c
+++ b/drivers/video/fbdev/msm/mdss_mdp_util.c
@@ -521,6 +521,11 @@ int mdss_mdp_get_img(struct msmfb_data *img, struct mdss_mdp_img_data *data)
 		}
 	}
 
+	if (!*start) {
+		pr_err("start address is zero!\n");
+		return -ENOMEM;
+	}
+
 	if (!ret && (img->offset < data->len)) {
 		data->addr += img->offset;
 		data->len -= img->offset;